1. Field of the Invention
The present invention relates in general to compressors and more particularly the compressors of a piston type that is widely used in a cooling system of automotive air conditioners.
2. Description of the Related Art
In order to clarify the task of the present invention, a piston type compressor disclosed in Laid-open Japanese Patent Application (Tokkai-hei) 9-280168 will be briefly described. In fact, the compressor of this publication is of a so-called wobble plate piston type that has a wobble plate for inducing reciprocating movement of pistons.
The compressor of the publication generally comprises a cylinder block in which a plurality of cylindrical piston bores are circularly arranged. The cylindrical piston bores accommodate respective pistons actuated by a wobble plate. A housing is attached to one end face of the cylinder block having a valve base plate disposed therebetween. The housing has an intake chamber defined therein. The valve base plate is formed with a plurality of intake openings through which the cylindrical piston bores are communicated with the intake chamber respectively. The intake openings are provided at the cylinder block side with respective reed valve elements for opening and closing the intake openings. That is, each intake opening and a corresponding reed valve element constitute a refrigerant intake valve. The reed valve elements are of a type having an enlarged leading end portion which actually opens and closes the corresponding intake opening. Stopper plates are provided at the end face of the cylinder block to regulate a lifting of the reed valve elements. Due to provision of the stopper plates, excessive opening movement of each reed valve element is suppressed and thus generation of undesired noise is prevented or at least minimized. For increasing a refrigerant intake efficiency of the intake valves, each reed valve element is constructed to have asymmetrical sides. Thus, under operation of the compressor, opening movement of the reed valve element is carried out along with a twisting motion of the same. With this, pressure loss caused by the operation of the intake valves is reduced and thus the refrigerant intake efficiency is increased.
However, due to inherent construction, the reed valve elements of the above-mentioned type tend to lower the responsiveness thereof. That is, in such reed valve element, starting of opening movement tends to be delayed as compared with a normal reed valve element that has symmetrical sides. If such delay is not small, satisfied increase in refrigerant intake efficiency of the intake valves is not expected.
Accordingly, an object of the present invention is to provide a piston type compressor that is free of the above-mentioned shortcoming.
That is, according to the present invention, there is provided a piston type compressor in which an opening movement of a reed valve element is carried out along with an assured twisting motion of the same without sacrificing the responsiveness.
According to a first aspect of the present invention, there is provided a piston type compressor for compressing a fluid, which comprises a cylinder block having at least one piston bore formed therein; a piston slidably received in the piston bore; a drive unit for sucking the fluid into the piston bore and compressing the fluid in the piston bore by using said piston; a housing having an intake chamber for taking the fluid thereinto, the housing being attached to one end of the cylinder block so that one end of the piston bore faces the intake chamber; a valve base plate disposed between the end of the cylinder block and the housing, the valve base plate having mutually isolated first and second intake openings through which the intake chamber and the piston bore are fluidly communicated; and an intake valve plate disposed between the end of the cylinder block and the valve base plate and having a reed valve element defined thereby, the reed valve element being arranged to open the first and second intake openings thereby to introduce the fluid into the piston bore from the intake chamber therethrough when the piston is moved away from the reed valve element and close the first and second intake openings thereby to stop the fluid introduction into the piston bore from the intake chamber when the piston is moved toward the reed valve element.
According to a second aspect of the present invention, there is provided a wobble plate piston type compressor for compressing a fluid, which comprises a cylinder block having at least one cylindrical piston bore formed therein; a piston slidably received in the piston bore; a wobble plate arranged to effect a wobble motion; a piston rod having end universally pivotally connected to the piston and the other end universally pivotally connected to the wobble plate; a housing having an intake chamber for taking the fluid thereinto, the housing being attached to one end of the cylinder block so that one end of the piston bore faces the intake chamber; a valve base plate disposed between the end of the cylinder block and the housing, the valve base plate having mutually isolated first and second intake openings through which the intake chamber and the piston bore are fluidly communicated; and an intake valve plate disposed between the end of the cylinder block and the valve base plate and having at least one reed valve element defined thereby, the reed valve being arranged to open the first and second intake openings thereby to introduce the fluid into the piston bore from the intake chamber therethrough when the piston is moved away from the reed valve element and close the first and second intake openings thereby to stop the fluid introduction into the piston bore from the intake chamber when the piston is moved toward the reed valve element, the reed valve element including an elastic arm portion which extends from an inner base portion of the intake valve plate along an imaginary center line, a first valve element part integral with the elastic arm portion and shaped and sized to open and close the first intake opening, the first valve element part being placed on the imaginary center line, and a second valve element part integral with the elastic arm portion and shaped and sized to open and close the second intake opening, the second valve element part being offset relative to the imaginary center line.